Trucks, Jeeps

2018 Jeep Wrangler: Engines, Gasoline and Diesel

2018 Wrangler JL engine bay

Bob Sheaves, who was responsible for 4x4 suspension design at the Jeep/Truck Engineering's PreProgram Engineering Department from the AMC days until 1993, wrote:

Lets take performance requirements first. Just what does Wrangler have to do?

To answer this you need to refer back to an SAE spec called J688 (superceded by J2188, but the 688 spec is easier to understand).

J688 predicts vehicle performance in highway speeds, fuel consumption, drag, and other variables. GM Truck and Bus division used to have a publicly available guide that showed how to specify what equipment to choose so it would meet the customer’s needs.

Chrysler’s most likely options

patent for heads

Currently, the rumor mill has two engines front and center:

  • Clarification: Bob Sheaves contributed ideas to this section, but did not write it.

    The Pentastar V6. While Sergio Marchionne has said that the 3.6 V6 would not be used, it now seems that it will, indeed, be the V6 for the 2018 Jeep Grand Cherokee (versus the smaller 3.2 liter engine). It appears that the efficiency of the 3.6 has been increased enough to make this practical now. However, it might not be the base engine for the base “Sport” model. That honor might go to...
  • The Hurricane Four. This is a turbocharged four cylinder under development for some time now. Details about this engine are sparse, but it will not simply be a rehash of the 2.4 SRT engine used in the Caliber SRT4. Instead, it is a completely new effort based on, but different quite a bit from, the current TigerShark 2.0 series.

2.8 liter VM diesel

  • A diesel will continue for European sale and possibly, especially if VM or Fiat can get the emissions right, for the United States. This will probably depend partly on whether demand for the Ram 1500 diesel and Jeep Grand Cherokee diesel continues — currently 20% of Ram 1500s come with the VM engine.
    • The 3.0 V6 used in the Ram and Grand Cherokee simply cannot fit into the JL Wrangler, especially since it appears that the appearance and “hard points” of the previous generation WK Wrangler will be maintained (partly to reduce the risk, given the switch of aluminum). This engine would also add quite a bit to the cost, and would be hard to produce in sufficient quantity given VM’s existing constraints, though using it would mean less inventory and fewer part numbers in the system.
    • RA 428 diesel engine from VM MotoriGM makes a VM-based 2.8 liter diesel engine and VM itself has a redesign in store. Jeep Wranglers have long used these VM diesels in Europe; the new design should push out over 200 horsepower, with more torque than the current V6. The engine has a new cooled EGR system, new manifolds, and a new block and balance shafts. It should be possible to make it meet U.S. emissions, as GM’s version does.
    • VM was creating a new L424 engine, another four-cylinder of 2.4 liters, which according to Alessandro Bettini’s dissertation was destined for the European Wrangler in 2013 (it seems to be late). This engine was to have a peak 200 horsepower, similar to GM’s version of the new 2.8, with 368 lb-ft of torque at 1600 rpm (almost identical to the VM 2.8!). The current 3.6 pushes out 260 lb-ft — the 3.2, 239 lb-ft. The injection system is only a little lower-pressure than the V6; it has solenoid-based direct injection, and EGR with high and low pressures, to reduce emissions to US ULEV standards.
    • There were also rumors of a new Fiat Powertrain diesel in the F1A family, but this is most likely due for the Ducato and ProMaster. The F1 family is probably too rough for civilian buyers. (Ivan Barišić wrote that the 2.3 F1A and 3.0 F1C are Fiat Commercial engines, built in Foggia.)
    • More likely is a Alfa Romeo 2.2 liter diesel which actually shows up in Chrysler’s parts system, associated with the Chrysler 200, according to Larry Vellequette of Automotive News. This is used in the European Jeep Cherokee, without the “Alfa Romeo” name.
DIESELSFiat L424VM 2.8 Gas. V6Alfa 2.2 diesel
Horsepower200197~ 292178
Torque (lb-ft)368368260332
  • A straight-six gasoline engine, perhaps based on the four-cylinders or perhaps on the Pentastar Six. This is exceedingly unlikely for numerous reasons, not the least of which is the increased length of the engine bay that would be needed. Development costs would be high for a single-car engine. However, the upcoming “completely new” corporate FCA engine family (likely to be credited to Alfa Romeo or another premium Italian brand, not FCA or Chrysler) is modular and could spawn a small straight six for use by different brands, according to Ivan Barišić.

Using the eight-speed automatic should allow diesels to be more practical, despite their relatively low horsepower and power range. It also makes turbocharged four-cylinders less of a burden, thanks to the combination of a lower first gear and a higher top gear.

Torson AWD in ZF aautomatic transmission

Allpar’s prediction is that the 2018 Jeep Wrangler JL will launch with conventional gasoline engines, the 2.0 Hurricane for base models and the 3.6 V6 for Rubicon and possibly optional on other lines. This would provide a gas mileage boost — despite the extra weight — while still providing ample torque for off-roading (especially with the eight-speed automatic). The engineers would probably prefer to stick with just four-cylinders, to allow more room for suspension articulation and easy packaging, but customers are likely to demand a six even if the four-cylinder can produce more horsepower and torque.


How to build it?

Pickups?

Steel or aluminum?

New suspension

Unit-body, frame...?
2018 Jeep Wrangler
Open or fixed top?
Transmissions
Transmissions
weight
Weight and strength
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